Watching aircraft in wartime
The Royal Observer Corps helped track aircraft movements during the Second World War. Trained volunteers reported aircraft they could see and hear, supplementing radar reports and helping the air defence system follow aircraft over Britain. A surviving photograph identifies West Mersea volunteer Granville L. Chambers in Observer Corps uniform.
The wartime observation arrangements should not be confused with the island’s later Cold War monitoring installation. They had different purposes and belonged to different phases of the Corps’ history.
The underground post beside Victoria Esplanade
Colchester’s archaeological record identifies a Cold War nuclear-monitoring post close to the junction of Victoria Esplanade and Empress Avenue, on the south side of the esplanade near the car park and putting green. The record dates it to approximately 1960–68.
It has been demolished, and the archaeological survey records no surviving trace. The location in the monument record is a former site, not an accessible surviving bunker.
A different job during the Cold War
After the Second World War, the Royal Observer Corps was given a role monitoring nuclear attack. Underground post crews were trained to identify explosions, measure radiation and report observations to control centres. The system was concerned with civil-defence information rather than shooting at aircraft or directing coastal guns.
Although the national network of monitoring posts continued until 1991, West Mersea’s recorded post had ceased operating much earlier. The years 1960–68 refer to this particular site, not to the whole Royal Observer Corps.
Site and service records
Colchester Heritage Explorer: West Mersea nuclear-monitoring post, MCC5572 · English Heritage: the Corps’ nuclear-monitoring role.
The island’s separate gun-defence history is covered in West Mersea coastal artillery battery.